2021 Toyota Highlander

Subtle issues showed early when trying to accelerate to get on the freeway, the transmission would stall. It was intermittent so, difficult to show at the dealership. At around 50,000 miles I began feeling a drag in the transmission, like it was put in downhill mode. Again, it happened intermittently. At 60,000 it would lunge slightly forward when I put it in park. At 63,000 I started hearing a whining sound at acceleration. The dealership did not address my concerns until it was out of warranty and then they said I needed a new transmission.

I own a 2021 Toyota Highlander with approximately 100,500 miles. The vehicle has developed a noticeable whining noise coming from the transmission/drivetrain area that continues to worsen over time. The noise is most noticeable during acceleration and while driving at highway speeds. I brought the vehicle to Toyota for inspection and was informed that the issue is related to the transmission. However, Toyota denied repair assistance because the vehicle is outside the powertrain warranty period. After researching the issue, I discovered multiple similar complaints involving 2021 Toyota Highlanders equipped with the UA80 transmission, including Toyota Technical Service Bulletin T-SB-0008-21 regarding “Whine or Grind Noise From the Transmission.” The symptoms described in the bulletin closely match the symptoms my vehicle is experiencing. Toyota appears aware of this transmission-related issue, yet many owners outside the warranty period are being denied coverage despite similar failures and complaints. I am concerned this may represent a broader transmission defect that could lead to premature transmission failure, unsafe driving conditions, hesitation, loss of power, or expensive repairs for consumers. I believe this issue should be investigated further by NHTSA due to the growing number of similar complaints involving whining transmission noises and transmission failures in Toyota Highlander vehicles. At this time, the vehicle has not yet experienced a complete transmission failure, but the condition is worsening and raises significant concerns regarding reliability and safety.

My 2021 Toyota Highlander was making a high pitched whine sound upon acceleration with the sound level holding steady at a consistent speed. We took the vehicle to a Toyota dealership to have it looked at and were told the transmission needs to be replaced. No other warnings were received. We are concerned about our safety if the transmission goes out while on the road.

What component or system failed or malfunctioned, and is it available for inspection upon request? - Transmission is in the process of failing. Yes it is available for inspection. How was your safety or the safety of others put at risk? - Loss of power train while driving could put the operator and the public at risk. Has the problem been reproduced or confirmed by a dealer or independent service center? - Yes, I've been told by two separate Toyota dealers that my transmission needs to be replaced. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? - Yes. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? - No.

2021 Toyota Highlander XSE AWD with approximately 60,400 miles. Vehicle has developed a noticeable driveline/transmission humming/whining noise during acceleration, beginning at lower speeds and increasing with vehicle speed under throttle. Noise is most noticeable while pressing the accelerator and appears consistent with Toyota T-SB-0008-21 regarding transmission whine/grind concerns on UA80F transmissions.

My 2021 Toyota Highlander equipped with the UA80 transmission developed a whining/grinding noise under acceleration around 73,000 miles. Toyota diagnosed internal transmission failure and recommended full replacement costing approximately $9,000. Toyota issued TSB T-SB-0008-21 acknowledging defects involving the front carrier assembly pinion shafts in these transmissions. This defect creates a potential safety hazard due to possible loss of power or drivability during highway operation. I am requesting that NHTSA investigate the widespread transmission failures affecting 2021 Highlanders and related Toyota vehicles.